1. Field
Example embodiments relate to a location tracking apparatus and a location tracking method, and more particularly, to a location tracking apparatus and location tracking method that may control an intensity of an ultrasound and an emission period used to track a location.
2. Description of the Related Art
Ultrasound is sound waves with a frequency greater than an audible frequency and cannot be heard by a human.
Since a refractive index of the ultrasound is greater than a refractive index of light, propagation is possible even though a small obstacle is in front. Also, since there is an advantage in that designing a complex filter is not necessary, the ultrasound may be used to measure an absolute distance of an object.
As an example of measuring the absolute distance of the object using ultrasound, there may be a method of using a time difference between a transmitting time of the ultrasound from a transmitting unit and a receiving time of the transmitted ultrasound at a receiving unit, when the transmitting unit and receiving unit of the ultrasound are synchronized. As another example, there may be a method that transmits ultrasound together with an infrared ray or a radio frequency from the transmitting unit and uses a difference between a velocity of sound and a velocity of light.
Ultrasound may be used to measure a location of an object together with a sensor that may provide relative location information, such as an inertial measurement unit (IMU), and the like.